Compound Interest Calculator
Free compound interest calculator — updated for 2025. Accurate, instant, no sign-up needed.
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Compound Interest Calculator
See how your investments and savings grow over time
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Future Value
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Interest Earned
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Total Invested
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Real Value (inflation adj.)
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Return on Investment
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| Year | Balance | Total Invested | Interest Earned | Real Value |
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The Power of Compound Interest
Compound interest earns returns on both your principal AND all previously earned interest — creating exponential growth.
A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)]
💡 Rule of 72: Divide 72 by your rate to find years to double your money. At 8%, money doubles every 9 years.
What returns are realistic in 2025?
S&P 500 index funds average ~10%/year historically (~7% after inflation). High-yield savings accounts offer 4.5–5.2% APY. Use 6–8% for conservative long-term planning.